Diversity of human rotavirus VP6, VP7, and VP4 in Lagos state, Nigeria

This study investigated the diversity of rotavirus strains recovered from young children in Lagos, Nigeria, during December 1996-January 1997. In total, 287 children, aged 1-60 month(s), presenting with diarrhoea to the Gbaja Health Centre of Massey Street Children Hospital and the Lagos University Teaching Hospital, were included in the study. Rotavirus-positive specimens were characterized by monoclonal antibody enzyme-linked immunosorbent assay (ELISA) for VP6 subgroup and VP7 serotype and by polymerase chain reaction (PCR) for VP4 genotype and VP7 strains (that were non-reactive to ELISA). Of 84 samples tested for VP6 subgroup epitope, subgroup 11 was predominant (51%) with only a few subgroup I strains (4%), while many could not be typed at all (45%). For the VP7 serotypes, G I was the most prevalent strain (45%), followed by G3 strains (5%). Neither G2 nor G4 strains were found, although mixed G1/G2 has been reported for the first time in Nigeria. Of strains that were non-reactive to ELISA, 29 (34%) could not be typed by PCR for G type, A subset of 23 samples was selected on the basis of RNA electropherotype, VP7 serotype, and included nine strains of VP7 that were non-reactive to ELISA. VP4 genotype of this subset was determined by PCR, and the most prevalent genotype was P[6] (30%), followed by P[8] (26%). Only one P[4] strain was identified. This study has shown the diversity of rotavirus strains circulating in West Africa.